Help with 340 compression + cam change

nm9stheham said

You don't use the intake closing at .050" to compute DCR....the DCR number is
computed with intake closing at or near the advertised duration numbers. So 8.02 is not correct for an 8.5 SCR..... Buuut DCR does correspond closely to cranking compression, and if you have 150-160 psi cranking compression, then your DCR is close to 8. (Meaning that the SCR has to be higher than 8.5....or the valves are doing something unexpected when cranking.)

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OK, it looks like I'm going to have to assume I have a CR higher than I thought, for whatever reason. So, in order to use the intake closing "advertised" as opposed to what is on the cam card, how is that determined?

One of the reasons I've struggled to figure some things is that this motor never seems to follow what I read about, or others tell me. It likes a fairly cold plug (Autolite 63), it runs fine on 89 but I usually use 91 (it does have the polished chambers and I remember filing the piston edges), it really likes an A/F mix quite a bit richer than what any charts recommend (it wants jetting pretty rich, with sencondaries 3-4 sizes bigger than primaries.) And this is based on both my A/F meter AND many test runs with careful plug readings. Seat of the pants says it really wakes up WOT if I'm seeing A/F of 10.8-11 on the meter. (maybe that's normal, but not the 12.5 some charts list for WOT)

My strip times aren't good, but most from before I figured a lot of this out, before sorting out the combination of timing and curve, A/F, etc. (missed my main events this year due to family stuff, and the test runs I did do I had it jetted way leaner than it should have been.)